The present invention relates to a hot air blowing gun and, more particularly, to a safety hot air blowing gun, which uses a protective cap to protect the user from contacting the hot nozzle during operation and, which defines a particular air passage around the nozzle for the passing of cold air to reduce the temperature of the protective cap.
FIG. 1 shows a hot air blowing gun according to the prior art. This structure of hot air blowing gun comprises a housing A, an inner barrel and nozzle assembly C mounted inside the housing A and partially projecting out of the front side of the housing A, a high-impedance resistance type heating element (not shown) wound round the inside wall of the inner barrel and nozzle assembly C, and a fan motor assembly B mounted inside the housing A behind the inner barrel and nozzle assembly C and controlled to blow currents of air through the inner barrel and nozzle assembly C to the outside of the hot air blowing gun for application. This structure of hot air blowing gun is functional, however it has drawbacks. Because the nozzle of the inner barrel and nozzle assembly C projects out of the front side of the housing A, the user may touch the hot nozzle of the inner barrel and nozzle assembly C by an accident during the operation of the hot air blowing gun.
During the operation of the hot air blowing gun, the temperature of the high-impedance resistance type heating element is as high as 500xcx9c600xc2x0 C. and the nozzle of the inner barrel and nozzle assembly C is continuously heated by hot air passing through. When touching the hot nozzle of the inner barrel and nozzle assembly C by an accident, the hand will be severely scalded with the hot nozzle. Further, the inner barrel and nozzle assembly C has a metal locating -ring D disposed around the periphery and fastened to the inside wall of the housing A. Because the locating ring D is fastened to the inside wall of the housing A, it prohibits cold air from passing through the gap between the outside wall of the inner barrel and nozzle assembly C and the inside wall of the housing A to reduce the temperature of the body of the nozzle of the inner barrel and nozzle assembly C. After a certain length of time in operation, the temperature of the nozzle of the inner barrel and nozzle assembly C may become higher than the melting point of certain materials, for example, wood, plastics, paper, and etc. When touching materials of low melting point with the hot nozzle of the inner barrel and nozzle assembly C, the materials may be burned, causing a disaster.
The present invention has been accomplished to provide a hot air blowing gun, which eliminates the aforesaid drawbacks. It is the main object of the present invention to provide a hot air blowing gun, which is safe in use. According to one aspect of the present invention, the hot air blowing gun comprises a housing, an inner barrel mounted inside the housing and holding a high-impedance resistance type heating element around the inside wall thereof, a tapered, hollow, cylindrical nozzle fastened to the front side of the housing and spaced around the front side of the inner barrel, the nozzle having a slotted outward positioning flange fastened to the front side of the housing and spaced around the periphery of the inner barrel by a gap for ventilation, a fan motor assembly mounted inside the housing behind the inner barrel and controlled to blow air through the inner barrel and the nozzle, and a hollow, tapered protective cap fastened to the front side of the housing and suspended around the nozzle to prohibit the user from touching the nozzle. According to another aspect of the present invention, the protective cap is suspended around the periphery of the inner barrel, having a slotted, outwardly extended locating flange fastened to the inside wall of the housing. During operation hot air passes through the inner diameter of the inner barrel and the inner diameter of the nozzle to the outside of the hot air blowing gun for application, and cold air passes through the gap between the outside wall of the nozzle and the inside wall of the housing to reduce the temperature of the outside wall of the nozzle. According to still another aspect of the present invention, a gap is defined between the inside wall of the protective cap and the outside wall of the nozzle for the passing of cold air to minimize transferring of heat from the nozzle to the protective cap.